1. Field of Invention
The present invention relates to a rock splitter of oil hydraulic piston type, and more particularly, a rock splitter of oil hydraulic piston type, in which a piston inserted into a hole perforating through rock rises and falls depending on a supply of oil.
2. Description of Prior Art
In general, a rock splitter of oil hydraulic piston type splits rock through a procedure by which a housing is inserted into a hole perforating through the rock and a piston rises and falls to split the rock when oil is supplied to the housing.
Referring to the drawings, the conventional rock splitter will be described hereinafter.
FIG. 1 is an exploded perspective view of the conventional rock splitter. FIG. 2 is a sectional view of an assembled state of the conventional rock splitter before operation. FIG. 3 is a sectional view of an assembled state of the conventional rock splitter after operation.
As shown in the drawings, The rock splitter 100 includes a housing 110 for inserting into a hole perforating through rock.
The housing 110 has an arch-shaped surface at the lower portion thereof for preventing the formation of gaps between the hole formed in the rock and the housing 110. The housing 110 further has a plurality of cylinder chambers 111 formed in the upper portion of the housing 110 at prescribed intervals, and has first and second paths 114 and 115 formed at one side portion thereof for supplying and discharging oil.
When the first path 114 is supplied with oil, a piston 130, which will be described hereinafter, is extended, and when the second path 115 is supplied with oil, the piston 130 is retracted.
Each of the cylinder 111 of the housing 110 includes a folding and unfolding means 120 capable of folding and unfolding to prevent excessive oil from being supplied inside the cylinder chamber 111 of the housing 110, thereby preventing damage to the housing 110 by overload. The folding and unfolding means 120 includes a fixing member 121 coupled with piston 130, a locking member 123 having a threaded portion 124 formed on the outer surface of the locking member 123 for engaging to a threaded portion 113 formed on the inner surface of the cylinder chamber 11, and a connecting member 122 for connecting the fixing member 121 to locking member 123.
The piston 130 is located on the folding and unfolding means 120 which is inserted into the cylinder chamber 111. The piston 130 includes a stepped portion 132 formed on a lower portion of the outer circumference thereof, a pair of grooves 133 formed on the outer surface of the stepped portion 132, first and second O-shaped rings 134 and 135 inserted into grooves 133 for preventing the outflow of oil from the cylinder chamber 111, and a hole 131 formed upper center portion of the piston 130 in which a screw 140 is inserted for connecting the piston 130 to the fixing member 121 of the folding and unfolding means 120.
In order to seal the hole 131 after screw 140 is inserted therein, a sealing member 150 is mounted on the end of the hole 131.
In order to prevent separation of the rising piston 130 from the cylinder chamber 111, a threaded portion 161 of a cylinder chamber 160 is engaged to a threaded connecting portion 112 of the cylinder chamber 111.
The cylinder chamber 160 includes a sealing member 162 which is inserted into the upper end portion from the lower end portion preventing the inflow of alien substances into the cylinder chamber 111 and a third O-shaped ring 163 inserted within the cylinder cover 160 for preventing the outflow of oil from cylinder chamber 111.
The piston 130 is formed in an arc shape at the upper end surface to facilitate maximum contact with the rock.
The conventional rock splitter 100 with the above structure is assembled into the configuration depicted in FIG. 2 through the following procedure.
The folding and unfolding means 120 comprised of the fixing member 121, the connecting member 122 and locking member 123 is inserted into cylinder chamber 111 of housing 110. The threaded portion 124 of the folding and unfolding means 120 engages the threaded portion 113 formed on the inner surface of cylinder chamber 111. The screw 140 is inserted into hole 131 of the piston in which the first and second 0-shaped rings 134 and 135 are inserted. The screw 140 is fixed to the fixing member 121 of the folding and unfolding means 120, so that the piston 130 is connected with the folding and unfolding means 120. The hole 131 of the piston 130 is sealed by this sealing member 150. After that the sealing member 162 and the third 0-shaped ring 163 fasten to the cylinder cover 160. The threaded portion 161 of the cylinder cover 160 connects to the threaded connecting portion 112 of the cylinder chamber 111, which is located on its inner circumference.
FIG. 2 a sectional view of the assembled state of the conventional rock splitter before operation. FIG. 3 a sectional view of the assembled state of the conventional rock splitter after extension of the piston 130 from the cylinder chamber 111.
When oil is supplied through the first path 114 of the housing 110, the supplied oil flows into cylinder chamber 111 through gaps formed between the members 121, 122 and 123 of the folding and unfolding member 120.
The piston 130 inserted into the cylinder chamber 111 extends due to the rising oil pressure and the extending piston 130 discharges the oil supplied inside the cylinder chamber 111 between the piston 130 and the cylinder cover 160 through the second path 115 of the housing 110.
Meanwhile, the pressure on the rock caused by the extending piston 130 splits the rock. After that, the folding and unfolding means 120 (including the fixing member 121, the connecting member 122 and the locking member 123) is expanded by the fixing member 121 connected to the piston 130 as shown in FIG. 3.
In the expanded state of the folding and unfolding means 120, as shown in FIG. 3, the gaps 125 (See FIG. 2) formed between members 121, 122 and 123 are sealed, so that oil supplied through the first path 114 is no longer supplied to cylinder chamber 111, thereby limiting the amount of oil supplied inside the cylinder chamber 111.
After splitting the rock, when oil is supplied to the second path 115 of the housing 110, the oil flows into the cylinder chamber 111 between the cylinder cover 160 and the piston 130, and thereby the rock splitter 100 is returned to its original condition. At this time, the expanded folding and unfolding means 120 is folded by retraction of the piston 130 such that the gaps 125 are again formed between the members 121,122 and 123. The oil, which is supplied within the cylinder 111 of the lower end of the piston 130 through the first path 114, is discharged through the gaps 125 to the first path 114, so that the rock splitter 100 is returned to its original condition.
However, because the piston 130 of the conventional rock splitter 100 extends inside the cylinder chamber 111 of the housing 110 by virtue of the high pressure of the oil supplied through the first and second paths 114 and 115, the piston 130 often deviates from its original position inside the cylinder chamber 111 due to the repetitive extension and retraction operation. The deviated piston 130 scratches the inner surface of the cylinder chamber 111 when the piston extends, and thereby the cylinder chamber 111 is damaged and oil leakage occurs through the gap 125 formed between the cylinder 111 and the piston 130. Therefore, the rock splitter 100 cannot perform its function, at which time the housing 110 must be replaced. Therefore, there are several disadvantages which decrease efficiency of work, while component expenses and maintenance fees increase.
It was explained that the piston 130 has the arch-shaped surface for maximizing the contact area to the rock. However, since the contact area is limited to the area of the piston 130, it is restricted to maximize the power applied to the rock.
When the folding and unfolding means 120 spreads with the rising piston 130, as shown in FIG. 3, the fixing member 121 is forcibly inserted into the connecting member 122, and the connecting member 122 into the locking member 123. At this time, too much power is required to fold the members 121, 122 and 123, so that the members 121,122 and 123 do not fold smoothly and the falling operation of the piston 130 is not performed smoothly.
Accordingly, it is an object of the present invention to overcome the disadvantages in the prior art by providing a rock splitter of oil hydraulic piston type, which includes an extra cylinder and cap, such that when the cylinder is damaged only the damaged cylinder is replaced, thereby improving efficiency of the work and reducing the maintenance fees.
It is another object of the present invention to provide a rock splitter of oil hydraulic piston type, which has a cap of an arc shape, such that the entire front surface of the cap touches the rock, thereby increasing the contact area to the rock and maximizing the power applied to the rock.
It is another object of the present invention to provide a rock splitter of oil hydraulic piston type, in which a connecting structure of members of a folding and unfolding means is improved, so that when returning to its normal state after operation, the collapsible member can be easily folded to its original condition, thereby preventing malfunction of the folding and unfolding means.
The foregoing objects are accomplished in one embodiment by providing a rock splitter of oil hydraulic piston type, which comprises a housing having a plurality of cylinder chambers formed on the upper portion and first and second paths communicated with the cylinder chambers for supplying and discharging oil; a piston inserted into the cylinder chamber of the housing, the piston rising and falling depending on the inflow of oil; and a cap being capable of vertical movement, the cap being connected to the upper surface of the housing in such a manner that the inner surface thereof is in contact with the upper surface of the housing, the cap moving vertically depending on the movement of the piston. The rock splitter further comprises: a cylinder detachably mounted inside the cylinder chamber of the housing in a sealing state; a collapsible member having a locking member detachably mounted in the cylinder chamber of the lower end of the piston, a plurality of members capable of a vertical extension, which are connected inside the locking member, inner and outer circumferences of the members having a gap for flowing the oil, and an elastic member supporting the lower end of the central member of the members and providing the elasticity to contacting the upper end of the member to the lower surface of the piston; and a plurality of stepped portions formed on the inner and outer circumferences of the members, each upper surface or lower surface of the stepped portion being in close contact with each lower surface or upper surface thereof to stop the gaps between the members and to prevent the flow of oil when the collapsible member spreads completely.
The cap is moveably mounted on the piston and has a pair to guide holes formed on opposite sides thereof. The housing has a pair of guide pins, which are formed on opposite sides thereof and slidingly inserted into the guide holes.
The cylinder includes a concave portion formed along the entire outer circumference thereof and communicated with the second path of the housing and a plurality of oil paths formed within the concave portion for allowing the oil supplied to the second path of the housing to flow into the cylinder. The piston has a concave portion formed on the upper end of a stepped portion thereof, the concave portion forming a space between the cylinder and the piston for allowing the oil to flow into the cylinder through the oil paths easily and for allowing the oil pressure to be applied to the stepped portion of the piston.
A plurality of rings are rearranged on the outer and inner surfaces of the cylinder and on the outer surface of the piston to maintain the sealing state between the cylinder chamber and the cylinder between the cylinder and the piston. Wear rings are arranged on the outer surface of the piston and on the inner surface of the cylinder to prevent lateral movement of the piston when the piston rises.